Let `f (x)= [x]` where `[x]` denotes the greatest integer contained in x. Which one of the following is correct ?

If f(x)=[2x], where [.] denotes the greatest integer function,then

Let f(x)=(-1)^([x]) where [.] denotes the greatest integer function),then

If f(x) =[|x|] where [.] denotes the greatest integer function , then which of the following is not true ?

Let f(x)=[|x|] where [.] denotes the greatest integer function, then f'(-1) is

Let f(x)=[|x|] where [.] denotes the greatest integer function, then f'(-1) is

If f(x)= [sin^2x] (where [.] denotes the greatest integer function ) then :

f(x)=log(x-[x]), which [,] denotes the greatest integer function.

Let f(x)=[x]+sqrt(x-[x]), where [.] denotes the greatest integer function.Then

If f(x)=cos[(x^(2))/(2)]x+sin[-(x^(2))/(2)]x where [.] denotes the greatest integer function, thenwhich of the following is not correct